1. Field
Exemplary embodiments of the present invention relate to a semiconductor design technology, and more particularly, to a semiconductor device which performs a circuit operation according to a command inputted from outside.
2. Description of the Related Art
In general, a semiconductor memory device including double data rate synchronous DRAM (DDR SDRAM) receives various command signals from outside and performs various operations corresponding to the command signals. For example, the semiconductor memory device may perform an active operation, a precharge operation, a write operation, and a read operation in response to the external command signals. The external command signals inputted to the semiconductor memory device may include a chip select signal, a row address strobe (RAS) signal, a column address strobe (CAS) signal, a write enable signal and the like.